3. Technical pens. Nonvariable width of line, but infinite variety of sizes and colors, since you fill it yourself. You can mix colors, dilute strengths, whatever you want. High maintenance, particulary in smallest nib sizes. More expensive. If you go this route, read up on maintenance.http://www.dickblick.com/zz210/03/

4. Cheap bic pen - the kind you find on the floor. See work by maori boy, dolors, and drwells.